1. The Field of the Invention
The present invention pertains to a system allowing wet steam to be allocated among priority and secondary users and, in particular, to a system which will measure the mass rate and quality of steam delivered to each user to facilitate proper billing for steam usage.
2. The Prior Art
There are many instances when wet steam supplied from a single generating source is divided among multiple users of the steam for whatever their purpose. Thus it is important to be able to divide steam between multiple users and to allocate the steam to each user according to a scheme which is defined by the arrangement of a custody transfer system within an overall steam distribution piping system.
It can be appreciated that wet steam will normally leave the steam generator or source at a known quality, pressure and mass flow rate. It is important, therefore, as a matter of economic practicality that a means be instituted to control distribution and quality of the steam. It is desirable that this be automatic to allocate steam between a multiplicity of users according to predetermined allocation schemes, such as distribution to a single priority user and one or more secondary users. The purpose of such a custody transfer system would be to monitor each user's consumption of steam such that each user will be charged only for the amount of steam actually consumed.
The measurement or monitoring of steam quality is important to determine steam usage for proper billing. Steam quality is a direct measurement of the heat contained in the steam and therefore represents the amount of fuel used to generate the steam and thus its cost.
In brief, it is desirable that the quality of steam, that is the mass of the steam vapor divided by the total mass, and that the mass flow rate be known and that the amount of steam consumed by each user likewise be known.